for循环中使用&&多条件判断无输出，如何打印6-9？

Hey there! Let's break down why your code isn't producing any output and fix it up.

First, let's look at your original code:

#include<stdio.h> 
int main(void) { 
    for(int i = 0; (i > 5) && (i < 10); i++) 
        // 打印数字 
        printf("%d\n",i); 
    return 0; 
}

Why no output? #

The core issue is your loop's starting value and condition. You initialize i to 0, but your loop only runs when (i > 5) && (i < 10) is true. Since 0 is way below 5, this condition fails immediately—your loop never even starts, so the printf line never gets executed.

Fixed Code #

To print numbers 6 through 9, we need to adjust the loop to start at the right value and stop at the correct point:

#include<stdio.h> 
int main(void) { 
    // Start i at 6, run as long as i is less than 10 (so i hits 6,7,8,9)
    for(int i = 6; i < 10; i++) 
        printf("%d\n",i); 
    return 0; 
}

Alternative Approach (if you want explicit range checks) #

If you prefer to keep a broader loop and filter values inside it, this works too—though the first approach is more efficient:

#include<stdio.h> 
int main(void) { 
    for(int i = 0; i < 10; i++) {
        if(i >= 6) { // Only print when i is 6 or higher
            printf("%d\n",i);
        }
    }
    return 0; 
}

内容的提问来源于stack exchange，提问作者SQLLER